PUBLIC HEALTH ASSESSMENT
WESTBOROUGH, WORCESTER COUNTY, MASSACHUSETTS
The Hocomonco Pond NPL site is located in Westborough, Massachusetts approximately 30 miles west of Boston and ten miles east of Worcester. A wood treatment facility was situated on the site from 1928 to 1946. Creosote wastes containing potentially carcinogenic Polynuclear Aromatic Hydrocarbons (PAHs) were disposed in a lagoon immediately south of Hocomonco Pond and in Kettle Pond immediately southeast of Hocomonco Pond. In 1976, an open-jointed underground drainage pipe was unknowingly routed through the former lagoon and, as a result, PAH contamination drained into the pond. PAH contamination has also been detected in sediment at the southeast edge of the pond. Fish sampled from the pond were found to contain elevated PAH levels and fishing activity has been observed in the pond waters near the area of elevated sediment contamination. The consumption of these fish and dermal contact with PAH contaminated sediments constitute completed exposure pathways. The site thus poses a public health hazard because of the potential risk to human health resulting from exposure to PAHs as a result of ingestion of contaminated fish and dermal contact with sediments at the pond. Local health officials have expressed concern with the health hazards associated with these exposures. The remediation planned by the United States Environmental Protection Agency (USEPA) will adequately reduce the health risk associated with dermal contact of contaminated sediments at the Hocomonco Pond. Review of the data from the Massachusetts Cancer Registry did not demonstrate any elevations in cancer rates that may be attributed to potential exposure to contaminants detected at the site. Numerous recommendations are made in order to protect the health of individuals engaged in activities in and around the site. Such recommendations include that fish indigenous to pond water be monitored to determine when they are safe for consumption and that individuals heed the posted warnings against fishing and swimming in pond waters.
This Public Health Assessment for the Hocomonco Pond site has been evaluated by ATSDR's Health Activities Recommendation Panel to determine appropriate follow-up activities. The panel has determined that follow-up activities are not indicated at this time. Some of the public health actions to be conducted by MDPH include the contined monitoring of cancer incidence rates for the town of Westborough and evaluation of monitoring results for fish caught from Hocomonco Pond, if such results should become available. This last action will enable public health officials to determine if consumption of fish caught from Hocomonco Pond continues to pose a health hazard.
The Hocomonco Pond National Priorities List (NPL) site is situated in the town of Westborough approximately thirty miles west of Boston and ten miles east of Worcester. Hocomonco Pond is on a twenty three acre site and is bounded on the east by Otis Street and to the south by Smith Valve Parkway. The southern and eastern edges of the pond serve as the site's north boundaries. A storm drain pipe running to the pond's southwestern edge bounds the site to the west. Also located on the site is Kettle Pond, a small depression, approximately 200 feet southeast of Hocomonco Pond. A stream flows southerly into Hocomonco Pond from the north. In addition, two storm drains discharge into the southern edge of the pond. Hocomonco Pond is drained by a discharge stream which joins with the Assabet River approximately one half mile northeast of the pond (see Figure 1). The site is currently owned by the town of Westborough and use of the site is restricted to remedial activities conducted by the potentially responsible parties and overseen by state and federal environmental officials.
The site in its early history housed a wood treatment plant and remnants of this operation still remain. The bases of tanks once used for storage of creosote, a wood preservative, are located on a bluff situated immediately south of the pond, forty feet above its surface. A steep decline leads from this area to the edge of the pond. Remnants of a factory where wood treatment operations were conducted are situated immediately southwest of the tank farm. A lagoon where creosote wastes were once deposited is located immediately south of the tank farm. A fenced area immediately southwest of the former lagoon area serves as a staging area for ongoing remediation efforts. Located immediately to the west of the site is a factory operated by Bose Incorporated, manufacturers of sound system components. A pharmaceutical manufacturing plant is situated immediately north of the pond.
As previously stated, the site once housed a wood treatment plant, where large amounts of creosote were stored and used. Waste creosote was disposed of in the lagoon east of the factory as well as in Kettle Pond. These operations took place between 1928 and 1946. In 1946, wood treatment operations ceased and the lagoon was backfilled. At this time, asphalt mixing operations began on the site and continued until a cement manufacturing company purchased the property. It is not known when this occurred. In 1976, the Smith Valve Company began operations at the plant currently operated by Bose Inc. The former wood treatment plant has since been abandoned and only remnants of the operation remain.
In 1976, a storm drain was constructed that ran underground from Smith Valve Parkway through the lagoon and discharged into Hocomonco Pond. As a result of the drainage system placement, creosote wastes would seep through joints in the system's conduits. During rainy periods road surface runoff running through the drainage system discharged lagoon wastes into the pond. Fish kills were reported in 1979 and 1982. Other site contamination movement occurred during construction on Otis Street in 1983, when contaminated soil from Kettle Pond was excavated and piled between Kettle Pond and Otis Street.
As a result of the contamination detected on the site, in 1985, the Centers for Disease Control (CDC) Superfund Implementation Group reviewed environmental monitoring data collected at that time. The group concluded that hazardous exposure to contaminated soil, sediment and ground water detected on the site was unlikely. The report released by the group, however, recommended that additional contaminant monitoring of fish caught from Hocomonco Pond is necessary in order to determine whether consumption of these fish poses a health risk. Hocomonco Pond was placed on the NPL in 1983. Also in 1985, a Record of Decision (ROD) was signed and it was determined that ground water from Kettle Pond would be pumped and treated and that the sediments from Kettle Pond would be excavated and buried in a lined landfill to be constructed on site. In addition, the contaminated sediments from Hocomonco Pond and discharge stream were to be dredged. These dredgings would also be deposited in the landfill. The ROD also stated that the surface of the former lagoon would be regraded and capped. The storm drain that ran through the former lagoon was also to be relocated. This relocation was completed in 1990.
While conducting investigations necessary for completion of the selected remedial plan, numerous boulders were discovered near Kettle Pond. In addition, the flow of ground water in the area was heavier than originally thought. It was determined that excavation in the area would compromise the structural integrity of Otis Street. Based on the greater than anticipated ground water flow near Kettle Pond and the inability to effectively excavate near Otis Street and Kettle Pond, it was determined that the original remedial plan for the Kettle Pond area was not feasible. In June of 1992 an Explanation of Significant Differences (ESD) was adopted by EPA and a surrogate plan was selected. The USEPA and the Massachusetts Department of Environmental Protection (MDEP) currently plan to remediate Kettle Pond by dredging the upper five feet of sediment and soil from the Pond. The deeper soils beneath Kettle Pond will be treated with microbes that will break down creosote components.
A site visit was conducted on June 24, 1992 by William Strohsnitter, Environmental Analyst for the Massachusetts Department of Public Health (MDPH) and the EPA Remedial Project Manager for the site. The pond was easily accessed by foot. It was also evident that vehicular access could also be attained. Although signs were posted along Otis Street prohibiting fishing or swimming in pond waters, one individual was observed fishing at the pond's southwest edge down stream of the drainage pipe discharge point. An oily sheen was noted on the pond's edge where fishing activity was observed. Creosote stains were also noted in the surface soil near the tank farm remnants and on the rocks at the discharge point of the storm drain. Given the fair summer weather conditions on the day the site visit was conducted, surprisingly no school-aged children were noted at the site. A non-restricting fence was observed at the easterly discharge point which runs northerly along Otis Street toward the pharmaceutical plant, which is situated immediately north of the site. The staging area, where remedial equipment is kept when such activities are ongoing, was secured by barbed wire fencing as were two monitoring wells from where raw creosote was recovered.
The culvert that drains Hocomonco Pond to the east traversed Otis Street and discharged to a small stream and marshy area east of Otis Street. Heavy brush and bramble growth appeared to prevent access to this heavily contaminated area. Evidence of fishing activity was observed 100 feet east of this point in another heavily contaminated area of the stream.
The population of Westborough according to the 1990 Census is 14,133. According to the 1980 Census, 278 people live within an approximate one mile radius of the site. The elderly (persons aged 65 years or greater) comprised 9.7% (n=27) of the population within this radius compared to 9.9% (n=1,325) for the remainder of the town. Thirty per cent (n=83) of those residing within the approximate one mile radius of the site were less than eighteen years of age and 26.8% (n=3,579) of those Westborough residents living outside of this radius were in this age category.
The area near the site is sparsely populated with approximately eighty people living on Fisher Street, one quarter of a mile south of the site. The area in which the site is located is zoned for light industrial and commercial use. The site is located approximately 4,000 feet south of Route 9, a major thoroughfare running the entire length of the state. An automobile dealership is situated on the corner of Otis Street & Route 9. A pharmaceutical manufacturing plant is located immediately north of the site on Otis Street. A produce farm is located immediately north of the pharmaceutical company.
The Conrail Railroad runs east to west immediately south of the Smith Valve Parkway and north of Fisher Street. The vast area south of the railroad is predominantly marsh land. A pond was formed in the area by the damming of the Assabet River. The community's water needs are served by several well fields situated throughout Westborough, the closest being 1,100 feet upgradient of Hocomonco Pond. In addition, a surface water reservoir is located three miles southwest of the site. There is currently no evidence that a private well survey has been conducted, however, the drinking water needs of some Westborough citizens are served by private wells.
Although signs are posted prohibiting such actions, fishing activity was observed on the pond during the site visit. According to the individual observed fishing, swimming also occurs in the pond. The site is also reported to serve as an evening gathering spot (TRC, 1984). No evidence of loitering or swimming, however, was observed during the site visit. A baseball playing field is located on the southern side of Smith Valve Parkway across from the site. There are two process wells at the former Smith Valve plant near the western edge of Hocomonco Pond. Their depth and usage are not currently known.
In order to ascertain if any adverse health effects were experienced in the community, available cancer incidence data (1982-1988) from the Massachusetts Cancer Registry (MCR) were reviewed. This database is maintained within the MDPH. Massachusetts law mandates that all hospitals within the Commonwealth report to the MCR, all incident cancer cases diagnosed within their facility. Pertinent information such as the age, sex, and residence of the cases is also maintained by the registry. Cancer incidence has been recorded in the Commonwealth since 1982.
There are no apparent health concerns regarding the site that are currently being voiced within the community. A public meeting was convened in Westborough by USEPA and the MDEP to discuss changes in the remedial plan for the site. Four citizens attended this meeting mostly for informational purposes. The small amount of citizen concern was also reiterated by the health officer of the town of Westborough. He concluded that the site is not of public concern primarily due to its non-threatening appearance. He did express concern about the health impact associated with swimming and fishing in the pond waters. In addition, he has a concern with the possibility of the creation of nuisance odors generated during the bioremedial process.